Thursday, December 27, 2007

The Energy of Aurora Borealis

SCIENTISTS think they have discovered the energy source of Aurora Borealis, the spectacular colour displays seen in the upper latitudes of the Northern Hemisphere.

New data from Nasa's Themis mission, a quintet of satellites launched recently, found the energy comes from a stream of charged particles from the sun flowing like a current through twisted bundles of magnetic fields connecting Earth's upper atmosphere to the sun.

The energy is then abruptly released in the form of a shimmering display of lights, said Vassilis Angelopoulos of the University of California at Los Angeles.

In March, the satellites detected a burst of Northern Lights over Alaska and Canada.

During the two-hour light show, the satellites measured particle flow and magnetic fields from space.

To scientists' surprise, the geomagnetic storm powering the auroras raced 645km in a minute across the sky.

Angelopoulos estimated the power of the storm was equal to the energy released by a magnitude 5.5 earthquake.

Although researchers have suspected the existence of wound-up bundles of magnetic fields that provide energy for the auroras, the phenomenon was not confirmed until May, when the satellites became the first to map their structure some 40,000 miles above the Earth's surface।
Source: New Straits Times